He attended the city"s public schools, and after graduation worked as a mechanic for three years. Schoenborn enrolled at the Technical Institute and School of Art in 1843 in Erfurt, where he studied architecture.
He emigrated to the United States in 1849 and settled in Wisconsin. Two years later, he moved to Washington, District of Columbia In June 1851, he found a position as a draftsman under Thomas U. Walter, Architect of the Capitol. With only a small scale model and some very rough drawings to work from, Schoenborn produced highly detailed architectural plans.
Walter did not initially believe that Schoeborn had done the work himself, but was quickly satisifed that Schoenborn was a trained architect.
President Millard Fillmore was also highly impressed with Schoeborn"s work, and often visited him in the architectural offices at the Capitol. Schoeborn made two important contributions to the United States Capitol.
When the Capitol library burned on December 24, 1851, it was replaced with an iron library which was designed by Schoeborn. Schoenborn also made the original drawings for the new iron dome of the Capitol.
When the American Civil War broke out in April 1861, Schoenborn worked as a surveyor and mapmaker for Union Army General Irvin McDowell in Virginia.
He also drew numerous plans for barracks, hospitals, and offices for the Quartermaster General of the United States Army. He returned to work on the Capitol in May 1862. Schoenborn spent the post-war years in Washington designing numerous public buildings, for which he became very well known.
He died at his home in Washington on January 24, 1902, at the age of 74.